Occupancy, Square Footage, or Hybrid: Which RUBS Method Should You Use?

For water and sewer, occupancy-based allocation is usually the best fit because water use follows people, not floor space. Square footage works better for utilities that follow space, such as shared heat. Hybrid blends the two. The right choice is the one that matches how the utility is actually used, is disclosed in your lease, and can be changed by you.

That last part is the one nobody talks about. The method is a decision you make once. The question is whether your billing partner lets you make it, or makes it for you.

The three methods, from the owner's seat

Occupancy. Each unit's share is its occupants divided by total occupants. Best for water, sewer, and trash. It tracks usage well and is easy to explain. The tradeoff: you have to keep occupant counts current, which means collecting them at move-in and lease changes.

Square footage. Each unit's share is its square feet divided by total rentable square feet. It is simple and needs no occupant data, which is why some owners like it. The tradeoff: a single person in a large unit pays more than a family of four in a small one. That is hard to defend for water.

Hybrid. A weighted blend, for example 70 percent occupancy and 30 percent square footage. Many operators land here because it balances both drivers and softens the edges of each method.

Some owners also weight occupancy so the first occupants count fully and additional ones count less, which reflects how households really use water. It is worth asking whether your software supports that.

A worked example

A 20 unit building receives a $3,000 water and sewer bill. You keep 10 percent for common areas, $300, which leaves $2,700 to allocate. The building has 36 occupants. A two-person unit carries 2/36, or 5.56 percent: $150.12.

Run the same building on square footage and that unit's share could land noticeably higher or lower depending on its size. That swing is why this decision deserves ten minutes, not a default.

How much should you deduct for common areas?

There is no universal number, and be careful of anyone who gives you one. It depends on irrigation, laundry, pools, and vacant units. As an example, many properties set something like 20 percent for water and sewer and 5 percent for trash, then adjust after reviewing a few months of bills. The point is that a common area deduction should be yours to set and change, with the reasoning written down.

What happens when you pick wrong?

Not much, if you can change it. Plenty, if you can't. I've watched owners stuck with a method chosen by a vendor onboarding rep years ago, because changing it meant a support ticket and a delay. Meanwhile their residents were being billed on a formula that no longer matched the building.

Ask your billing partner these three things

1. Can I choose and change the method myself, per property and per utility?
2. Can I set the common area deduction, and see how it affects each resident?
3. Is the method written into every bill so there is nothing to argue about?

On our platform you set all three yourself. If your current vendor makes you submit a request, that is worth knowing before you renew.

See how allocation and deductions work in the software: https://calendly.com/utilityranger/demo

FAQ

What is the most common RUBS allocation method?

Occupancy-based allocation for water, sewer, and trash, and square footage or hybrid where the utility tracks space.

Is square footage RUBS fair?

It is defensible for utilities that follow space, but weaker for water, since a single occupant in a large unit would pay more than a family in a small one.

What is a hybrid RUBS formula?

A weighted blend of occupancy and square footage, such as 70 percent occupancy and 30 percent square footage.

How do I set a common area deduction?

Review several months of bills against what the common areas use, set a percentage, and adjust as conditions change. Document your reasoning.

Can I change my allocation method later?

Yes in most cases, but check your lease terms and give residents proper notice. Your software should let you change it without a vendor request.